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Mid-America Transportation Center

Safety Performance Evaluation of Posts for use in a New Short Radius Guardrail for Intersecting Roadways


Researchers

  • Principal Investigator: John Reid (jreid1@unl.edu 402-472-3084)
  • Co-Principal Investigator: Karla Lechtenberg (kpolivka2@unl.edu 402-472-9070)
  • Co-Principal Investigator: Ronald Faller (rfaller1@unl.edu 402-472-6864)
  • Project Status
    In Progress
    About this Project
    Brief Project Description & Background
    Guardrail systems used along roadways are intended to redirect impacting vehicle or in the case of short-radius guardrail, capture the vehicle at certain impact points. Kinetic energy is dissipated during any impact event through the deformation of the rail and posts and post rotation through the soil. This dissipated energy reduces the risk of injury to the vehicle's occupants. Previous development of a short radius system has shown significant improvement over the existing system. Unfortunately, the system length and backside space requirements made the system impractical to use in most real-world applications. In addition, any necessary improvements to help the system meet the current safety performance criteria would only further increase the system length. Therefore, a need exists to develop a new barrier system that can be used near intersecting roadways, driveways, and streets that would meet the MASH TL-3 safety performance criteria.
    Research Objective
    A significant amount of data exists from numerous dynamic post testing studies. However, this data is located among many different research reports and is presented in different formats. Thus, creating a database from the extensive amount of data available will allow researchers to easily utilize the data in order to compare the performance characteristics of different posts. The analysis of the post performances will then be used during the concept development phase of the project.
    Potential Benefits
    The research study will aid in the development of an impact attenuation system for intersecting roadways. This research will help evaluate the performance of posts to be used in the new system. The dynamic post testing database will also be an invaluable tool for future studies.
    Abstract
    Guardrail systems used along roadways are intended to redirect impacting vehicle or in the case of short-radius guardrail, capture the vehicle at certain impact points. Kinetic energy is dissipated during any impact event through the deformation of the rail and posts and post rotation through the soil. This dissipated energy reduces the risk of injury to the vehicle's occupants.

    Previous development of a short radius system has shown significant improvement over the existing NCHRP 230-compliant system. Unfortunately, the system length and backside space requirements made the system impractical to use in most real-world applications. In addition, any necessary improvements to help the system meet the current safety performance criteria would only further increase the system length. Therefore, a need exists to develop a new barrier system that can be used near intersecting roadways, driveways, and streets that would meet the MASH TL-3 safety performance criteria.

    The current project of developing an impact attenuation system (short radius system) for intersection roadways has funding to conduct background research on previous short-radius designs and for concept development. However, further research is needed to evaluate different post sizes and types that could potentially be utilized during concept development. Therefore, this proposal seeks to supplement the concept development of a new short-radius system for intersecting roadways.
    Project Amount
    $ 60,000